<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>houzi</title>
    
    <script type="text/javascript">
     function taozi() {

         var i = 1;
         for(var day =1;day <=9; day++){
             i = 2 *(i +1);
             console.log("第"+day+"天"+"有"+i+"个");

         } 


   }
   taozi();

    </script>
</head>
<body>
    
</body>
</html>